The present invention provides an essentially tamper-proof security cap for use with a pipe union and particularly to provide a cover for the union nut associated with the union where the union nut is not in use or connected to an associate fitting.
More particularly, in certain fire protection systems which include sprinkler systems with multiple sprinkler heads in a building and adapted to be actuated automatically in response to a fire or extreme heat the actuation of several sprinkler heads causes a loss of pressure with resulting loss of coverage area of individual sprinklers heads since the area of coverage is directly dependent on the pressure of the water supply. Water supply systems for sprinklers are maintained either in a water full of dry condition but in any event operate from available water main pressure and supply which in most instances is not sufficient to maintain optimum operating pressure when there are several sprinkler heads in operation.
Also in certain applications where a sprinkler system is not provided in a building but a fire control system utilizing fire hoses located at selected locations in the building and where the fire control system includes an inlet connection external of the building so that fire suppression personnel can connect an auxiliary fire water supply to the system.
Accordingly, the National Fire Protection Association Code Section 207.1 requires a connection through which a fire department can pump water into the sprinkler system or fire control system except where permission of an appropriate local jurisdiction has been secured to eliminate the connections. Where such connections are provided, upon arrival of fire suppression personnel an auxiliary source of water supply, usually a hose supplied with water from a fire hydrant, is connected to the connection where the connection is advantageously located outside the building and in most instances in a public location accessable to vandals or subject to inadvertent damage. In most cases, a hose connection including a union with a union nut is the connection provided and National Fire Protection Association Code Section 2-7.6.2 specifies that such hose connections shall be equipped with plugs or caps.
The plugs or caps are provided to be attached to the union nut to cover the auxiliary water inlet to the sprinkler system to prevent vandalism and inadvertant introduction of trash or other debris to the water inlet which would clog the sprinkler system when it is needed most.
Such hose connections are usually called siamese connections and are fitted with union nuts having an internal thread to match the thread of the hose of the local fire department, in most cases a male connection of a fire hose. Also, in most instances, the union nut is loosely retained on the inlet pipe and is provided with radially extending parts adapted to be operated by a "spanner" wrench carried by most firefighters.
Several types of caps or plugs have heretofore been provided to be secured to the union nut of siamese connections to protect the integrity and operability of the system to supply water to the sprinkler system. One such cover is a brass plug having external threads to be received in the union nut where the plug, like the union nut, is provided with radially extending posts to be operated by a spanner wrench.
The union nut of such siamese connections is usually brass so it is necessary to provide brass plugs, which are of substantial scrap value so that, because of their location in public places, the plugs are frequently stolen.
An alternative arrangement which has been provided includes an easily breakable, for example cast iron cap which is attached to the union nut, for example by U-bolts carried by the cap but adapted to engage the posts of the union nut to hold the cap in place. Such cap members have been particularly vulnerable to vandalism and are particularly susceptible to breakage at the points where the U-bolts are received in the cap. Furthermore, even where the cap is not broken, certain portions of the cap are necessarily there and over a period of time rust through and the caps fall off. Also, because of the differences in coefficient of thermal expansion between the union nut and cap the cap is also susceptible to breakage.
Accordingly, it is desireable to provide a cover means for an outside sprinkler system which can be quickly and easily removed by a firefighter upon arrival at the scene of a fire so that a hose can be connected to the sprinkler system where the cap is not otherwise easily removed either intentionally or accidentally or likely to break away as a result of thermal or atmospheric conditions.